1. Field of the Invention
The present invention relates to a vehicle A.C. generator to be mounted into automobiles such as a passenger vehicle and a truck, and in particular, relates to an improved structure of a rotor in the vehicle A.C. generator.
2. Description of the Related Art
Vehicle A.C. generators have been well known and various types thereof are mounted to automobiles such as a passenger vehicle and a truck. Such a vehicle A.C. generator is comprised of a rotor and a stator. The rotor of the vehicle A.C. generator has a plurality of magnet poles of a pair of pole cores. The rotor has plural connecting members. Each connecting member connects and fixes a corresponding permanent magnet to an end plate of a corresponding pole core toward a rotary shaft of the rotor. In particular, the connecting member is extended from a magnet holder to an end plate connected to an end surface of the pole core toward the longitudinal direction of the magnet holder. The permanent magnet is contained in the magnet holder. For example, Japanese patent laid open publication No. JP H10-201149 has disclosed such a structure of the vehicle A.C. generator. (Pages 3 to 5, and FIGS. 1 to 15 in JP H10-201149).
On the other hand, Japanese patent laid open publication No. JP 2001-78374 has disclosed another type of the vehicle A.C. generator in which a magnet holder is placed between a pair of adjacent magnet poles, an extended part of the magnet holder is extended toward the direction of a rotary shaft of the rotor so that it projects toward an end surface of a pole core, and the part of the magnet holder serves as a cooling fan.
However, the conventional techniques of the vehicle A.C. generator described above have the following drawbacks.
In the structure of the vehicle A.C. generator disclosed in JP H10-2011489, the connecting member with which the magnet holder and the end plate are connected requires additional working steps for connecting the connecting member to the end plate of the corresponding pole core. In addition, this conventional technique requires additional components and thereby increases the number of components of the vehicle A.C. generator. As a result, the manufacturing cost of the vehicle A.C. generator is increased.
In the structure of the vehicle A.C. generator disclosed in the latter case, namely, JP 2001-78374, because a total length of the magnet holder including extended part becomes long, the strength of the extended part which serves as a cooling fan becomes low.